The following information is provided to assist the reader in understanding technologies disclosed below and the environment in which such technologies may typically be used. The terms used herein are not intended to be limited to any particular narrow interpretation unless clearly stated otherwise in this document. References set forth herein may facilitate understanding of the technologies or the background thereof. The disclosure of all references cited herein are incorporated by reference.
Many different types of life rafts are available for use by those forced to abandon a vessel at sea. In many cases, life raft users become wet first before boarding the life raft. Inflatable life rafts typically use carbon dioxide for inflation. Life rafts may include a canopy or other cover to protect users from cold waves and air. Periodic maintenance is typically required to identify defects such as punctures. In the case of an inflatable raft, even small puncture may make the raft dysfunctional. Life rafts may, for example, include separate air compartments to maintain buoyancy if one or more compartments leak. Maintenance for carbon dioxide inflatable rafts is a significant issue. For example, periodic maintenance is required and new carbon dioxide canisters must be purchased after each use. Further, the carbon dioxide canisters are made of stainless steel or other metal and are thus heavy. Pressure gauges on the canisters can often provide wrong information as a result of degradation, and users must often contact a specific supplier to buy carbon dioxide canisters having the right size, the right amount of carbon dioxide, and the right pressure.
Wearable immersion suits or survival suits have also been used to protect a user from hypothermia after immersion in water resulting from, for example, abandoning a ship or from partial immersion during fishing or other water activities. Such suits are typically formed from elastomeric materials with good insulation properties (for example, polyurethanes, rubbers, neoprenes, etc.). Immersion suits may, for example, include a plurality of air pockets inflatable by mouth, by carbon dioxide canisters, or by a small handheld air pump, to provide extra buoyancy and improved insulation. Wearable immersion suits may also include a stiff, waterproof zipper that does not allow water to enter the suit. In the chest area of a wearable immersion suit, accessories may be attached that help with rescue activities (for example, a whistle, an emergency strobe, an emergency radio locater beacon, a harness, a buddy line etc.). A buddy line may, for example, be used to connect to other users equipped with wearable immersion suits so that multiple people may stay together. In one type of immersion suit, the user may wear the suit all the time. Such wearable immersion suits are sized to fit a specific user and may provide more dexterity. Another type of wearable immersion suit is oversized so that anyone can wear the suit in case of emergency. Such oversized wearable immersion suits provides more space to the user, thereby providing more freedom in the suit and more space for different user sizes, but providing for less dexterity (as a result of bulkiness) as compared to the sized wearable immersion suits.
A number of wearable immersion suits protect the wearer from hypothermia by employing better insulating materials and by providing different buoyancy methods. Attempt to improve breathing include, for example, providing a straw-like breathing apparatus in case the head of the user becomes completely submerged. Nonetheless, wearable immersion suits have many drawbacks. For example, when the user is in the water, only the user's head and a portion of the user's shoulders are exposed to the air. Because about 80% of the user's body is submersed, there is a greater chance that the user's head may be completely submerged even in relatively calm seas. In addition, to facilitate breathing immersion suits may not adequately seal the user's face. The user's face and neck may thus become wet with cold water. An exposed face and neck can quickly suffer frostbite when exposed to extremely cold water and air. Further, having a wet face and neck is uncomfortable, and may cause the user to panic, particularly in rough, and/or cold seas. It's almost impossible to keep the entire body of the user of an immersion suit totally dry. Breathing air through an apparatus such as a straw may not be easy, particularly when the user's body is under constant motion as a result of waves. Often, the user may inhale water instead of air. The gap between the user's face and the suit's face shield may be less than one inch, leaving limited room to store air when waves are high and when the occupant is completely submerged. Such risks are dramatically increased in the presence of large (for example, 15 foot to 50 foot) waves. Such large waves may repeatedly hit the user's head. In addition to causing wetness and increasing breathing difficulty, large waves may also physically injure the user's head (for example, resulting in disorientation, loss of consciousness and/or a concussion injury). Head injuries present a very dangerous scenario as the user must maintain strong mental control and good breathing ability when in the water. Additionally, accessories provided with wearable immersion suits (for example, emergency strobe, first-aid kit, radio locater beacon, food, and water) are located on the outside of the suits, which makes it more difficult for the occupant to use the accessories and more difficult to maintain waterproof conditions.
Submarine escape immersion suits (SEIS) are another type water protection system that are typically designed for a single user. A SEIS may be turned into a single-user life raft upon surfacing. A SEIS is dependent on a carbon dioxide inflation system because it must ascend to the water surface as soon as possible, before high pressure and hypothermia start to affect the wearer. Hard-shelled, deep submarine rescue vehicles (DSRV) are also available and can simplify ejection methods when abandoning a submarine. A DSRV can provide several benefits to its crew members including, for example, a supply of oxygen, precise humidity control, and communication devices. A DSRV is made of steel, and is, in essence, a small version of a submarine. Operating and pricing are thus significant issues.